Quest Issue: Goblin Penmaster/Penkeeper

[Salem Orchid]

I've been killing the Goblin Penmaster, and Goblin Penkeeper + the placeholder in The Temple of Droga for the Iksar khurki quest, but have yet to see the "stone key" or the "stone necklace" drop. The "stone key" is supposed to be able to drop off both the Penkeeper and Penmaster, while the necklace is supposed to drop off the Penmaster.

I have probably camped the mob for 8 hours total so far, 1 spawn every 20 minutes, and seen the "bone key" drop 7 times... are the other items not on the loot table, or have I just been extremely unlucky?